Centrifugal suction pumps of the type having a vertically disposed support tube, a hollow hub rotatable mounted on the upper end of the support tube, and a plurality of horizontally exposed expeller tubes connected to the hub are known in the art. Centrifugal suction pumps of the type described utilize the centrifugal forces on liquid in the expired tubes as a consequence of rotation of the hub, for creating a suction in the support tube which draws liquid up the support tube and into the expression tubes thus achieving a pumping action.
U.S. Pat. No. 4419043 discloses a centrifugal suction pump of the type described, but the pump has a serious deficiency in that its priming is difficult, if not impossible, to accomplish. In other words, a centrifugal suction pump of the type described will operate properly only if the support and expeller tubes are filled with liquid. The '043 patent appears to be very difficult to prime. For this reason, proper operation of the pump is questionable.
U.S. Pat. No. 3519365 solves the priming problem by providing an external casing and immersing the expeller tubes in the liquid, but this creates a serious drag problem. Occasioned by rotation of the expeller tubes in the liquid. As a consequence, energy consumption for this pump is quite large. One disadvantage of centrifugal pumps utilizing an external casing is the difficulty and expensive in constructing expeller tubes which are long. This is a severe constraint that jeopardizes the efficiency of the pump and its capacity to pump large volumes of liquid.
It is therefore an object of the present invention to provide a new and improved centrifugal suction pump of the type described which substantially overcomes the problems encountered by prior art devices of the type described.